Materials looks different in viewport and in material preview

Pretty much like the title said, in my material preview everything looked fine and I even pick the mesh I want to preview in the material preview and it all worked fine, however, when I dragged the mesh into my scene it looked all glowing and weird. How do I fix this?

in material preview

in main viewport

I’m kinda wondering why you would have ANY emissive on a rifle? Try setting that param to 0.

I would suggest just having NOTHING on that pin (best way of getting a zero value :-))

Edit - but it might be good to show us something of the material that you’re using… how is it created, and how do separate different materials on the mesh. Easier for people to provide comment (and I’m a complete novice, so may not be able to provide a sensible answer anyway)